WO2001025854A1

WO2001025854A1 - Method for forming pattern

Info

Publication number: WO2001025854A1
Application number: PCT/JP2000/006940
Authority: WO
Inventors: Takashi Kanda; Hatsuyuki Tanaka
Original assignee: Clariant International Ltd.
Priority date: 1999-10-05
Filing date: 2000-10-04
Publication date: 2001-04-12
Also published as: CN1377477A; KR20020035169A; JP2001109165A; EP1223470A4; EP1223470A1

Abstract

A method for forming a coating layer (3) crosslinking in the presence of acid on a resist pattern (11) having a thickness of 2 νm or more and formed on a substrate (2), and crosslinking the coating layer (3) contiguous to the resist by diffusion of acid from the resist to the coating layer thereby to thicken the resist pattern and to decrease effectively the dimensions of space parts of a line-and-space pattern, a trench pattern, and a hole pattern, wherein the thickened patterns are prevented from deforming by irradiating the resist pattern (11) with visible light of wavelength band of 150-450 nm or ultraviolet radiation before and/or after forming the coating layer (3). A device, e.g. a magnetic head, can be fabricated faithfully as designed by plating a pattern thus formed.

Description

Description Pattern forming method Technical field

According to the present invention, after a resist pattern is formed, a coating layer that is crosslinked in the presence of an acid is provided on the pattern, and the coating layer adjacent to the resist is formed by utilizing the diffusion of the acid from the resist to the coating layer. To effectively reduce the size of space, such as line-and-space patterns, by cross-linking and thickening the resist pattern. More specifically, magnetic heads, micromachines, etc. The present invention relates to a method of providing a coating layer that is crosslinked in the presence of an acid on a thick-film resist pattern used in the manufacturing process of (1) to thicken the resist pattern and effectively reduce the size of the pattern. Background art

In a wide range of fields, such as the manufacture of semiconductor devices such as LSI, the production of flat panel displays (FPD) such as liquid crystal display (LCD) panels, the manufacture of circuit boards such as thermal heads, and the manufacture of magnetic heads, etc. Conventionally, photolithographic techniques have been used to form or perform microfabrication of microelements. In photolithography technology, a positive or negative photo resist is usually used to form a resist pattern. These positive or negative photo resists are coated on a substrate, aligned with a mask, exposed and developed to form a resist pattern. You. These formed resist patterns are used as, for example, etching resists in the manufacture of semiconductor devices, FPDs, circuit boards, and the like, and as resists in the manufacture of magnetic heads.

In recent years, with the high integration of semiconductor devices, etc., the wiring and separation width required for the manufacturing process have been increasingly miniaturized, and in response to this, the miniaturization of resist patterns using shorter wavelength light Various attempts have been made to form a fine resist pattern by using a phase shift mask, etc., and to develop a new register and a new process corresponding to these. . However, it is difficult to form a fine resist pattern exceeding the wavelength limit of the exposure wavelength by the conventional photolithography technology using exposure. On the other hand, a short wavelength exposure apparatus and a phase shifter are required. An apparatus using a mask or the like is expensive.

One method for solving such a problem is disclosed in

In Japanese Patent Publication No. 3448, Japanese Patent Application Laid-Open No. Hei 6-250739, Japanese Patent Application Laid-Open No. Hei 10-73927, etc., a conventionally known positive type or negative type photo resist is used. After a pattern is formed by a conventionally known pattern forming method, an acid-crosslinkable coating layer forming material layer is applied to the formed resist pattern, and the diffusion of acid from the resist panel by heating is used. After the material layer is cross-linked and cured to make it insoluble in the developer, the uncured portion is removed by development to thicken the resist pattern, and consequently the width between the resist patterns is reduced, thereby reducing the resist width. There has been proposed a method for forming a fine pattern in which a fine resist pattern is effectively formed with a resolution smaller than the resolution limit of the exposure wavelength in order to make the pattern finer. This method is for short wavelength Since the size of the space of the resist panel can be effectively reduced without making expensive capital investment such as an exposure apparatus, the method is attracting attention as a useful method.

The conventional pattern formation method proposed above was developed based on the premise that it would be applied to etching resist patterns with a very small resist film thickness of, for example, 1 m or less, such as for the production of semiconductor integrated circuits. It was done. When the thickness of the resist is not so large as described above, a coating layer that crosslinks in the presence of an acid is provided in the resist pattern, and crosslinking and curing of the coating layer forming material layer due to diffusion of the acid from the resist. Even if the resist pattern is made thicker by using it, there is no problem of the pattern deformation after development. However, when this method was applied to a resist pattern in which the thickness of a resist pattern was 2 Xm or more, as in the manufacture of a magnetic head micromachine, etc., the coating layer was developed after crosslinking. It was found that when the uncured part was removed, the formed pattern was inclined or deformed as if crushed, as shown in Figs. 3 (a) and (b). The form of the deformation of the pattern differs depending on the position of the pattern in the pattern image. For example, the deformation of the resist pattern shown in Fig. 3 (b), which is crushed, is seen near the center of the wafer or the like, that is, near the center of the pattern image, while on the other hand, Fig. 3 (a) Such a deformation as when the resist pattern is pulled to one side is seen at the periphery of the pattern image. If the resist pattern is deformed in this way, devices such as magnetic heads cannot be manufactured as designed, resulting in poor yield, poor coating layer formation efficiency, and insufficient miniaturization. Problems such as Live.

According to the present invention, a resist pattern having a thickness of 2 m or more is formed on a substrate to be processed by using photolithography technology, and a coating layer forming material that is crosslinked in the presence of an acid is formed on the resist pattern. A coating layer is formed by coating and cross-linking in the presence of an acid, and the coating layer adjacent to the resist pattern is cross-linked by diffusion of the acid from the resist pattern to thicken the resist pattern, thereby obtaining a liner. In a pattern formation method that can effectively reduce the size of a space pattern, trench pattern, hole pattern, etc. to below the critical resolution of the exposure wavelength, the pattern deformation after the resist pattern is fattened is reduced. To improve the efficiency of the formation of the cross-linking coating layer, thereby improving the design of devices such as magnetic heads based on the deformation of the resist pattern. Prevented without occurrence of defective products is to provide a method of forming a pattern conforming efficiently design. Disclosure of the invention

As a result of intensive studies and studies, the present inventors have found that, in the above-described pattern forming method, after forming two or more resist patterns on a substrate to be processed, the resist pattern is exposed to an acid on the resist pattern. As a step before or after the step of forming the coating layer to be bridged, a step of irradiating the resist pattern with visible light or ultraviolet light having a wavelength of 150 to 45 O nm can be added. The present inventors have found that deformation of the resist pattern after development of the coating layer can be prevented, and that the crosslinking of the coating layer is performed efficiently, and the present invention has been accomplished.

That is, the present invention provides a resist pattern having a film thickness of 2 m or more. A coating layer that crosslinks in the presence of an acid is provided thereon, and in the pattern forming method in which the coating layer is crosslinked by the diffusion of the acid from the resist pattern to increase the thickness of the resist pattern, a coating layer is formed before forming the coating layer. The present invention relates to a pattern forming method characterized by irradiating a resist pattern with visible light or ultraviolet light having a wavelength of 150 to 45 O nm after forming a coating layer.

In addition, the present invention relates to a method of manufacturing a magnetic head by forming a pattern by the above-described method, and further performing a plating process. BRIEF DESCRIPTION OF THE FIGURES

Fig. 1 shows the pattern shape of the present invention, which forms a thickened pattern by irradiating visible or ultraviolet light with a wavelength of 150 to 45 O nm after forming a coating layer on a resist pattern. FIG. 4 is an explanatory diagram for explaining one method of forming.

Fig. 2 shows that the resist pattern is irradiated with visible light or ultraviolet light having a wavelength of 150 to 450 nm, and then the resist pattern is thickened by forming a coating layer on the irradiated resist pattern. FIG. 9 is an explanatory view for explaining another method of forming a pattern according to the present invention.

FIG. 3 is an explanatory diagram of an example of a deformed pattern formed by a conventional technique. Detailed description of the invention

Hereinafter, the present invention will be described in more detail with reference to FIG. 1 and FIG.

FIG. 1 shows the state after forming the coating layer 3 on the resist pattern 11. In addition, the pattern forming method of the present invention in which irradiation with visible light or ultraviolet light having a wavelength of 150 to 450 nm is performed, and FIG. 2 shows that the resist pattern 11 is formed by applying the resist pattern 11 to a wavelength of 150 to 450 nm. The pattern forming method of the present invention in which the coating layer 3 is formed on the resist pattern that has been irradiated with visible light or ultraviolet light and then irradiated is described below.

First, in FIGS. 1 and 2, a resist pattern 11 having a film thickness of 2 m or more and capable of generating an acid by irradiation with visible light or ultraviolet light is formed on a substrate 2 to be processed. Is done. ((2) in FIG. 1 and (2) in FIG. 2) The resist pattern 11 is formed as follows using, for example, a photolithography method.

That is, first, a photoresist solution is applied onto the substrate 2 to be processed, and pre-baking (for example, baking temperature: 70 to: L40 * C for about 1 minute) is performed. A film 1 is formed ((1) in FIG. 1 and (1) in FIG. 2). The photoresist film 1 is exposed to ultraviolet rays such as g-rays and i-rays, far ultraviolet rays such as KrF excimer laser, and ArF excimer laser light, X-rays, and electron beams. After baking (PEB, e.g., bake temperature: 50 to 140 :), it is developed and, if necessary, post-development bake (e.g., bake temperature: 6). Then, the resist pattern 11 is formed.

The photo resist that can be used to form the resist pattern 11 may be any one that can form a resist pattern having a film thickness of 2 m or more. Type or negative type. Such photoresists include visible light at a wavelength of 150 to 45 O nm. Alternatively, it is preferable that an acid is generated by ultraviolet irradiation, and a positive or negative resist pattern is formed by the action of the generated acid. Examples of the photo-resist which can be preferably used for forming the photo-resist film 1 include, for example, no-polak resin, hydroxystyrene-based resin, acryl-based resin and other alkyd soluble resins and quinoline resins. A positive-type resist containing a diazide compound and a chemically amplified positive- or negative-type resist that generates an acid upon irradiation with light and forms a resist pattern by utilizing the catalytic action of the generated acid can be cited.

However, the photoresist used in the present invention does not necessarily have to be such that the photoresist material itself generates an acid upon irradiation with light as described above. In the case where the resist material itself does not generate an acid by light irradiation, for example, a material that generates an acid by light irradiation may be further added to the resist material.

In the present invention, a coating layer forming material is formed on the formed resist pattern 11 before or after irradiation with visible light or ultraviolet light having a wavelength of 150 to 450 nm after or after the formation of the resist pattern. It is applied to form the coating layer 3. ((3) in FIG. 1 and (4) in FIG. 2) Examples of the coating layer forming material that can be used in the present invention include a water-soluble resin, a cross-linking agent, and an aqueous solution containing a surfactant if necessary. The conductive resin composition is preferred. The water-soluble resin used in the water-soluble resin composition may be a homopolymer or a multi-component copolymer of a vinyl monomer containing a hydrophilic group, such as polyvinyl alcohol (including partially hydrolyzed), polyacrylic acid, and polyacrylic acid. Methacrylic acid, poly (2-hydroxy (Polyethyl acrylate), poly (2—hydroxy butyl acrylate), poly (4—hydroxy butyl acrylate), poly (4—hydroxy butyl methacrylate), poly (Glycosiloxy methacrylate), poly (glycosyl oxymethyl methacrylate), polyvinyl methyl ether, polyvinyl pyrrolidone, polyethylene glycol, polyvinyl acetal (including partially acetalized), polyethylene Imine, polyethylene oxide, styrene-maleic anhydride copolymer, polyvinylamine, polyallylamine, oxazoline group-containing water-soluble resin, water-soluble melamine resin, water-soluble urea resin, alkyd resin, sulfonamide Or salts thereof. These may be used alone or in combination of two or more. The molecular weight of the water-soluble resin is preferably from 1,000 to 10,000, more preferably from 2,000 to 5,000, in terms of weight average molecular weight. Preferred crosslinking agents are water-soluble crosslinking agents such as low-molecular-weight derivatives of melamine, low-molecular-weight guanamine, low-molecular-weight urea, glycolperyl, and alkoxyalkylated amino resins. It is listed as. Examples of the melamine-based low-molecular-weight derivatives of the water-soluble crosslinking agent include melamine, methoxymethylated melamine, ethoxymethylated melamine, propoxymethylated melamine, butoxymethylated melamine, and hexamethylol. Melamine and the like. Examples of guanamine-based low-molecular-weight derivatives include acetate guanamine, benzoguanamine, and methylated benzoguanamine. Examples of urea-based low-molecular-weight derivatives include urea, monomethylol urea, dimethylol urea, alkoxymethylene urea, N-alkoxymethylene urea, and ethyl urea. Examples include urea and ethylene urea carboxylic acid.

On the other hand, examples of the alkoxyalkylated amino resin include an alkoxyalkylated melamine resin, an alkoxyalkylated benzoguanamine resin, an alkoxyalkylated urea resin, and the like. Specifically, methoxymethylated melamine resin, ethoxy resin Cimethylated melamine resin, propoxymethylated melamine resin, butoxymethylated melamine resin, ethoxymethylated benzoguanamine resin, methoxymethylated urea resin, ethoxymethylated urine resin, propoxymethylated urea resin, butoxymethyl Urea resin.

These water-soluble cross-linking agents can be used alone or in combination of two or more kinds. The compounding amount is 100 to 100 parts by weight of water-soluble resin, 1 to 70 parts by weight, preferably 10 to 5 parts by weight. 0 parts by weight.

Examples of the surfactant include Florad manufactured by 3M, Nonipol manufactured by Sanyo Kasei, Megafac manufactured by Dainippon Ink and Chemicals, and acetylene represented by the following general formula (I). Examples include alcohols, acetylene glycols, acetylenic alcohols, and acetylenic alcohols.

General formula (I):

(Wherein, R ¹ represents a linear or branched alkyl group having 1 to 20 carbon atoms, and R ² and R ³ each independently represent H or a linear or branched alkyl group having 1 to 3 carbon atoms. R ⁴ represents a linear or branched alkylene group having 1 to 20 carbon atoms, k represents 0 or 1, and m and n each independently represent a positive number including 0. )

Among the surfactants, acetylene alcohols, acetylene glycols, polyethoxylates of acetylene alcohols, and polyethoxylates of acetylene glycols are preferred from the viewpoint of film-forming properties. Examples of acetylenic alcohols, acetylene glycols, polyethoxylates of acetylenic alcohols and polyethoxylates of acetylene glycols include 3 —methyl-1 —butyn-1- 3 —ol, 3 —methyl— 1 —pentin-3-ol , 3,6-Dimethyl-4-octyne-3,6-diol, 2,4,7,9-tetramethyl-l-5-decyne-l, 7-diol, 3,5-dimethyl-l-hexyne-l-ol, 2,5-Dimethyl-3-hexyne-2,5-diol, 2,5-dimethyl-2,5-hexanediol and polyethoxylates thereof, and the like, 2,4,7,9-te Particularly preferred are tetramethyldecine diols such as tramethyl-5-decyne-4,7-diol and polyethoxylates thereof. These surfactants can be used alone or in combination of two or more kinds. 0 0-1, OOO ppm.

The solvent used in the water-soluble resin composition of the present invention is a water-soluble resin Any material can be used as long as it can dissolve the components of the composition and does not dissolve the resist pattern already formed on the substrate to which the water-soluble resin composition is to be applied. Usually, as the solvent, a solvent containing at least water, specifically, water, preferably pure water or a mixture of water and an organic solvent soluble in water is used. Examples of the water-soluble organic solvent used by mixing with water include alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; acetone, methyl ethyl ketone, and the like.

—Ketones such as heptane and cyclohexanone; esters such as methyl acetate and ethyl acetate; ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether; Ethylene glycol monoalkyl acetates such as ethylene glycol monomethyl ether acetate and ethylene glycol monoethyl acetate; propylene glycol such as propylene glycol monomethyl ether and propylene glycol monoethyl ether; Monoalkyl ethers; propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether terecetate, and other propylene glycol monoalkyl ether teracetates; lactic acid Lactic esters such as methyl and ethyl lactate; aromatic hydrocarbons such as toluene and xylene; amides such as N, N-dimethylacetamide and N-methylpyrrolidone; lactones such as a-ptyrolactone; Examples thereof include polar solvents such as dimethylformamide, dimethyl sulfoxide, cellosolve, methylcellulose solvent, butylserumolate, cellosolve acetate, butyl carbitol, and carbitol acetate. Preferred organic solvents include lower alcohols having 1 to 4 carbon atoms, such as methyl alcohol, ethyl alcohol, and isopropyl alcohol. Particularly preferred is isopropyl alcohol. These organic solvents may be mixed as long as the resist pattern 11 is not dissolved.

In order to apply the coating layer forming material, for example, an appropriate method such as a spin coating method, a spraying method, a dipping method, a mouth coating method, and the like, which have been conventionally used for applying a photoresist, is used. You should. The applied coating layer forming material is prebaked as necessary to form the coating layer 3. Some of the coating layer forming materials are commercially available, such as AZR200 (manufactured by Clariant Japan; "AZ" is a registered trademark; the same applies hereinafter).

In the present invention, the wavelength 150 is formed after the resist pattern 11 is formed, before the coating layer 3 is formed on the resist pattern 11 or after the coating layer is formed on the resist pattern. The resist pattern is irradiated with visible light and ultraviolet light of ~ 450 nm ((4) in Fig. 1 and (3) in Fig. 2). In this irradiation treatment, the irradiation wavelength, irradiation time, irradiation intensity and the like may be selected in accordance with the characteristics of the resist pattern to be irradiated, and the irradiation conditions are not particularly limited. Irradiation devices include, for example, Hg lamps, g-line (wavelength 436 nm) or i-line (wavelength 365 ηm) irradiation devices, KrF excimer irradiation devices (wavelength 248 nm), K An rCl excimer irradiator (wavelength 222 nm), an Xe excimer irradiator (wavelength 172 nm), an XeCl excimer irradiator (wavelength 308 nm), and the like can be used. In addition, heating can be performed as necessary during the irradiation with visible light or ultraviolet light. In this irradiation treatment, it is sufficient to irradiate the whole pattern in its entirety, and if necessary, may irradiate only part of the pattern.

Acid is generated in the resist pattern by the above visible light or ultraviolet irradiation treatment. The acid generated in the resist pattern by this irradiation treatment and, if the acid already exists in the resist pattern, the diffusion of the acid further crosslinks the coating layer in the portion adjacent to the resist pattern, It hardens and becomes insoluble in the developer. If necessary, the resist pattern and the coating layer can be subjected to a heat treatment (mixing bake) to promote the diffusion of the acid. When mixing baking is performed, the baking temperature and the baking time may be appropriately determined depending on the resist used, the material for forming the coating layer, the desired cross-linked film thickness of the coating layer, and the like. When performing a mixing bake, the conditions are usually a temperature of about 85 to 150 and a time of about 60 to 120 seconds.

Further, the crosslinked coating layer is developed with water, a mixed solution of water and a water-soluble organic solvent, or an aqueous alkali solution such as TMAH (tetramethylammonium hydroxide), etc. The layer is dissolved and removed, and an undeformed pattern covered by the crosslinked coating layer 31 is obtained. ((5) in Fig. 1 and (5) in Fig. 2)

When the resist pattern is covered with a cross-linked coating layer, the resist pattern is further irradiated with visible light or ultraviolet light having a wavelength of 150 to 45 O nm to reduce the thickness of the resist pattern. The reason why no pattern is formed is not fully understood, but the generation of acid in the resist pattern is promoted by irradiation with visible light or ultraviolet light, and the curing of the resist pattern or the coating layer is promoted. It is presumed that it is because. BEST MODE FOR CARRYING OUT THE INVENTION

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but embodiments of the present invention are not limited to these examples. Example 1

A positive type photoresist AZP4210 (manufactured by Clariant Japan) is applied to a 6-inch silicon wafer with a spin coater (MK-V) manufactured by Tokyo Electron Co., Ltd. for 100 seconds and 120 seconds. Pre-baking was performed on a hot plate to form a resist film 1 of about 2.5 μm. Next, exposure (SSO m JZ cm ² ) was performed using an exposure apparatus (DSW640, NA = 0.42) manufactured by GCA having a g-line (436 nm) exposure wavelength. Spray paddle development for 1 minute under conditions of 23 using an alkali developer (AZ400K developer, inorganic alkali developer) manufactured by Ant Japan Co., Ltd. to obtain a line-and-space pattern. Obtained.

AZR200 (manufactured by Clariant Japan Co., Ltd.) is applied on the resist pattern with a spin coater (LT100) manufactured by Lithotech Japan Co., Ltd. as a coating layer forming material, and is applied for 85 and 70 seconds. Baking was performed on a plate to form a coating layer of 0.45 im. The entire surface of the coating layer was exposed using an exposure apparatus (DSW640, NA = 0.42, manufactured by GCA) having an exposure wavelength of g-line (436 nm).

Further, a mixing bake was performed using a hot plate for 110 and 90 seconds, and the crosslinking reaction was allowed to proceed. Under the development treatment for 1 minute, the uncrosslinked layer was peeled off, and a crosslinked layer of a water-soluble resin film was formed on the line, and space pattern. Further, baking treatment was performed for drying on a hot plate for 110 and 120 seconds.

Observation of the formed pattern with a scanning electron microscope (SEM) revealed no deformation in the resist pattern. Comparative Example 1

After forming the coating layer, a pattern was formed in the same manner as in Example 1 except that direct mixing baking was not performed without exposing the entire surface using a g-ray exposure apparatus. When the formed pattern was observed by SEM in the same manner as in Example 1, the pattern was deformed near the center of the wafer as if crushed as shown in Fig. 3 (b). As in a), the pattern was deformed as if it were pulled to one side.

Example 2

Instead of forming the coating layer on the resist pattern and then performing the entire exposure using the g-ray exposure device, after forming the resist pattern, performing the entire exposure using the g-ray exposure device and then forming the coating layer Except for this, a pattern thickened by the cross-linking coating layer was formed in the same manner as in Example 1. When the formed pattern was observed by SEM in the same manner as in Example 1, no deformation of the pattern was observed as in Example 1.

Example 3

The substrate having the thickened pattern obtained in Example 1 was further plated to form a plated layer having the designed width and shape. The invention's effect

As is clear from the above description, the coating layer is applied to the resist pattern having a thickness of 2 zm or more formed by the conventional method, and the coating layer is crosslinked and cured to form the resist pattern. When the line and space pattern, the trench pattern, or the hole pattern is effectively miniaturized by increasing the thickness, the resist pattern is formed on the resist pattern after the step of forming the resist pattern. Applying visible or ultraviolet light with a wavelength of 150 to 45 O nm before and / or after the process of forming the coating layer prevents deformation of the resist pattern, improves cross-linking efficiency, and is as designed. A device such as a magnetic head can be manufactured in a short time, thereby improving the manufacturing yield and manufacturing efficiency.

Claims

The scope of the claims

A coating layer that crosslinks in the presence of an acid is provided on a resist pattern having a thickness of 1.2 zm or more, and the coating layer is crosslinked by diffusion of an acid from the resist pattern to widen the resist pattern. In the pattern forming method, the resist pattern is irradiated with visible light or ultraviolet light having a wavelength of 150 to 450 nm before and / or after forming the coating layer. Forming method.

2. A method for manufacturing a magnetic head, further comprising: subjecting a pattern formed by the pattern forming method according to claim 1 to a plating process.